Weymouth and Melcombe Regis was a borough in England.
It was formed by a charter of Elizabeth I, amalgamating the towns of Weymouth and Melcombe Regis in 1571.
The towns continued to send the same number of MPs to the unreformed House of Commons as they had before the merger - two for each.
The borough was stripped of its double representation by the Reform Act 1832, which reduced it to two seats, and then was remodelled by the Municipal Reform Act 1835.
Since then, the area covered by the borough has formed part of the South Dorset constituency.